CVE-2026-80825 (GCVE-0-2026-80825)
Vulnerability from cvelistv5
Published
2026-09-04 15:54
Modified
2026-10-19 08:44
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7925: ensure tx headroom in usb_sdio_tx_prepare_skb mt7925_usb_sdio_tx_prepare_skb() pushes a TX descriptor and a USB header onto every skb and assumes the headroom for them is already there. That holds for locally generated traffic, where mac80211 reserves hw->extra_tx_headroom, but forwarded frames are sent through ieee80211_8023_xmit(), which does not reserve it. Bridge a wired interface to an mt7925u AP and the first forwarded frame that arrives short panics the kernel: skbuff: skb_under_panic: len:415 put:4 tail:0x19b end:0x640 dev:wlan1 kernel BUG at net/core/skbuff.c:212! Call trace: skb_panic+0x58/0x60 (P) skb_push+0x58/0x60 mt7925_usb_sdio_tx_prepare_skb+0xf8/0x1b8 [mt7925_common] mt76u_tx_queue_skb+0xa0/0x1f8 [mt76_usb] __mt76_tx_queue_skb+0x54/0xe8 [mt76] mt76_txq_schedule.part.0+0x204/0x478 [mt76] mt76_txq_schedule_all+0x50/0x80 [mt76] mt792x_tx_worker+0x68/0x100 [mt792x_lib] __mt76_worker_fn+0x84/0x150 [mt76] Whether a given setup hits it depends on how much headroom the ingress netdev leaves in its rx skbs. Reproduced on a Raspberry Pi 5 bridging onboard ethernet to a Netgear A9000; originally reported on an MT7986 router running OpenWrt. Nick Morrow's testing on a Pi 4 (bcmgenet), which leaves more headroom, helped narrow the trigger to the ingress path. The same bug was fixed on mt7921 by commit 98c4d0abf5c4 ("mt76: mt7921: don't assume adequate headroom for SDIO headers"), but mt7925 was copied from mt7921 without the fix. Add the same guard here.
References
Impacted products
Vendor Product Version
Linux Linux Version: c948b5da6bbec742b433138e3e3f9537a85af2e5
Version: c948b5da6bbec742b433138e3e3f9537a85af2e5
Version: c948b5da6bbec742b433138e3e3f9537a85af2e5
Version: c948b5da6bbec742b433138e3e3f9537a85af2e5
Version: c948b5da6bbec742b433138e3e3f9537a85af2e5
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/wireless/mediatek/mt76/mt7925/mac.c"
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          "programFiles": [
            "drivers/net/wireless/mediatek/mt76/mt7925/mac.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.7"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "version": "7.1.13",
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              "version": "7.2.3",
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              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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              "negate": false,
              "operator": "OR"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: mt76: mt7925: ensure tx headroom in usb_sdio_tx_prepare_skb\n\nmt7925_usb_sdio_tx_prepare_skb() pushes a TX descriptor and a USB\nheader onto every skb and assumes the headroom for them is already\nthere. That holds for locally generated traffic, where mac80211\nreserves hw-\u003eextra_tx_headroom, but forwarded frames are sent through\nieee80211_8023_xmit(), which does not reserve it. Bridge a wired\ninterface to an mt7925u AP and the first forwarded frame that arrives\nshort panics the kernel:\n\n skbuff: skb_under_panic: len:415 put:4 tail:0x19b end:0x640 dev:wlan1\n kernel BUG at net/core/skbuff.c:212!\n Call trace:\n  skb_panic+0x58/0x60 (P)\n  skb_push+0x58/0x60\n  mt7925_usb_sdio_tx_prepare_skb+0xf8/0x1b8 [mt7925_common]\n  mt76u_tx_queue_skb+0xa0/0x1f8 [mt76_usb]\n  __mt76_tx_queue_skb+0x54/0xe8 [mt76]\n  mt76_txq_schedule.part.0+0x204/0x478 [mt76]\n  mt76_txq_schedule_all+0x50/0x80 [mt76]\n  mt792x_tx_worker+0x68/0x100 [mt792x_lib]\n  __mt76_worker_fn+0x84/0x150 [mt76]\n\nWhether a given setup hits it depends on how much headroom the ingress\nnetdev leaves in its rx skbs. Reproduced on a Raspberry Pi 5 bridging\nonboard ethernet to a Netgear A9000; originally reported on an MT7986\nrouter running OpenWrt. Nick Morrow\u0027s testing on a Pi 4 (bcmgenet),\nwhich leaves more headroom, helped narrow the trigger to the ingress\npath.\n\nThe same bug was fixed on mt7921 by commit 98c4d0abf5c4 (\"mt76:\nmt7921: don\u0027t assume adequate headroom for SDIO headers\"), but mt7925\nwas copied from mt7921 without the fix. Add the same guard here."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:44:17.799Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/9a72b180f0575e41471e088e09bddc4b73d6dee2"
        },
        {
          "url": "https://git.kernel.org/stable/c/22edb6786127271aeba7abd30f152977c605c6a3"
        },
        {
          "url": "https://git.kernel.org/stable/c/8d481f93588932a95f657671d4e1601b90d130cc"
        },
        {
          "url": "https://git.kernel.org/stable/c/e5e8fc11a7ac578f16079f855b7fffc1649d053c"
        },
        {
          "url": "https://git.kernel.org/stable/c/ef3e34874d2332d0f63e72c2c35ce5c93568c125"
        }
      ],
      "title": "wifi: mt76: mt7925: ensure tx headroom in usb_sdio_tx_prepare_skb",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80825",
    "datePublished": "2026-09-04T15:54:29.224Z",
    "dateReserved": "2026-08-26T14:34:25.795Z",
    "dateUpdated": "2026-10-19T08:44:17.799Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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